Cellulose Nanofibers Content Research Articles

Bio-Templated Aerogel Fibers: Heterogeneous Spinodal Architecting and In Situ Fibrillation of Thermoplastic Polyurethane-Silica on Nanostructured Cellulose Nanofiber Scaffold for Enhanced Thermomechanical Performance.

This study addresses the inherent fragility and fractal limitations of traditional silica aerogels by developing a bio-templated aerogel fiber. Integrating cellulose nanofibers (CNFs), thermoplastic polyurethane (TPU), and silica aerogel (SA) in a dimethyl sulfoxide (DMSO) dispersion, a gel-spinning technique was employed to create aerogel fibers with superior thermomechanical performance. CNF also provided excellent rheological modification for successful spinnability, fast gelation, and fiber formation. The unique hierarchical structure of these fibers, formed through hot-stretching and surface modification, combined the superior mechanical strength and flexibility of TPU with the exceptional insulation properties of CNF and SA. The CNF network, encapsulated within the SA particles, formed a core-shell structure, axially aligned, that significantly enhances the thermal stability and mechanical performance of the fibers while maintaining a lightweight and porous architecture. Comprehensive morphological, thermal, and mechanical analyses were conducted to evaluate the properties of the developed aerogel fibers. Fourier transform infrared (FTIR) spectroscopy and nuclear magnetic resonance (NMR) spectroscopy verified the successful surface modification and grafting reactions on CNF, contributing to improved hydrophobicity and thermal insulation. Adjusting the CNF content allowed for tailoring of the thermomechanical characteristics, with a notable 294% increase in tensile strength from 5.3 to 15.6 MPa and an enhanced crystallization temperature from 106 to 119.97 °C. Furthermore, cyclic tensile and compression tests validated the durability and shape recovery capabilities of the aerogel fibers, making them promising candidates for high-performance applications in extreme environments. The thermal conductivity validated by experimental data further highlights the potential of CNF-based aerogel fibers as sustainable and multifunctional materials for advanced thermal insulation, mechanical reinforcement, and flexible structural applications.

Composite edible film mimicking cell wall based on arabinoxylan, β-glucan and nanocellulose: Microstructural, physico-chemical properties, and preservation effect

To achieve sustainable environmental development, various biodegradable films have been designed to replace plastic films. The cell walls of the wheat bran aleurone layers primarily comprise alternately overlapping arabinoxylan (AX), β-glucan (BG) and small quantities of cellulose and ferulic acid. The differences in their composition can affect their mechanical strength and hydration. Therefore, multilayer films of AX, BG, cellulose nanofibers (CNFs), and free ferulic acid were prepared to simulate the cell walls of wheat aleurone layers, and the effect of different CNF contents on cell walls characteristics was investigated. The microstructure, physical properties, and hydration characteristics of multilayer films were studied using scanning electron microscopy, time-domain nuclear magnetic resonance, and thermogravimetric analysis. The AX/BG/8%CNF multilayer films possessed excellent thermal stability and mechanical properties along with slow moisture diffusion and flowability. When the CNF content within the films was 8%, the polymer composite structure hindered the diffusion of moisture. Inspired by the biological effects of wheat grain cell walls, cellulose multilayer films were used for blueberries preservation, and the decay rate, weight loss index, and respiration rate of blueberries were found to decrease significantly.

Polyacrylamide/Cellulose Nanofibers Composite As Quasi Solid Electrolyte for Rechargeable Zinc-Ion-Battery

This research aims to optimize the cellulose nanofiber content in polyacrylamide (PAM) using as quasi-solid electrolyte composites for zinc-ion batteries (ZIBs). The cellulose nanofibers (CNFs) derived from hemp were prepared via alkaline treatment and bleaching process, followed by mechanical defibrillation. The chemical functional group analysis confirmed the successful extraction of lignin and cellulose from hemp fiber. The improved thermal stability of cellulose nanofibers indicated the success of the chemical treatment in removing non-cellulosic components. Furthermore, quasi-solid electrolyte composites of PAM / CNFs at 0.25, 0.5, 0.75, and 1 wt.% of cellulose nanofibers were prepared. At 1 wt.% CNFs addition, PAM / CNFs composites showed the highest values for electrolyte uptake, and electrochemical impedance spectroscopy with the highest ion conductivity of 59.6 mS cm-1. For the plating/stripping testing with symmetrical zinc cell, PAM / CNFs at 1.0 %wt CNF also demonstrated the lowest overpotential with the best zinc dendrite suppression feature. For zinc-ion battery performance test, the quasi-solid electrolyte composites of PAM / CNFs at 1.0 %wt CNF were fabricated and employed with electrochemical properties testing, including cyclic voltammetry, galvanostatic charge-discharge, electrochemical impedance spectroscopy, and cycle stability. This optimized quasi-solid electrolyte composites reached the highest specific capacity of 134.2 mA g-1 at a current density of 0.1 A g-1 and maintained capacity retention of 90.8% of initial capacity with 94.4% coulombic efficiency after 500 cycles.

P(MMA-co-MAA)/cellulose nanofibers composites: Effect of hydrogen bonds on molecular mobility

Cellulose nanofibers (CNFs) nanocomposites were prepared using poly(methylmethacrylate-co-methacrylic acid) (PMMA-co-MAA) to investigate the macromolecular mobility within the composite, with particular focus on the effect of H-bonding. Dynamic mechanical analysis (DMA) and broadband dielectric spectroscopy (BDS) were used to fully characterize the molecular mobility for which the effect of the introduction of H-bond forming moieties and the addition of CNFs (5 and 15 wt%) were assessed. Despite similar Tg values (determined by Differential Scanning Calorimetry), a deeper analysis of the relaxation times associated with the α-relaxation evidenced a significant effect induced by CNFs, which is in fact slowing down the macromolecular relaxation processes. The activation energy of the β-relaxation remained unchanged despite the introduction of MAA units in the main chain and the successive addition of CNFs. However, the latter led to the appearance at low frequencies of a new β’-relaxation correlated with the interactions between the CNF surface -OH groups and the -COOH groups of the matrix. The γ-relaxation showed a 45 % increase in activation energy from PMMA to PMMA-co-MAA + CNF nanocomposites regardless of the CNF content, due to the possibility of CNFs to interact and hinder the motion of the main chain methyl groups in α position.

Preparation of High-Toughness Cellulose Nanofiber/Polylactic Acid Bionanocomposite Films via Gel-like Cellulose Nanofibers.

This study demonstrates a procedure for preparing gel-like cellulose nanofibers (CNFs) in polyethylene glycol (PEG) to toughen polylactic acid (PLA) nanocomposite films. A well-dispersed solution of CNFs in ethanol was produced from microcrystalline cellulose by using a high-pressure microfluidizer. The fiber diameter of CNFs was found to be in the range of 80-100 nm. Ethanol was replaced by PEG using a rotary evaporator to obtain gel-like CNFs/PEG. PLA/PEG/CNF films were prepared using the solvent casting method, with the CNF content varying from 0.15 to 5 phr. The effect of CNFs on the mechanical, morphological, and thermal properties of PLA nanocomposite films was investigated. The results demonstrate that the addition of CNFs improved Young's modulus and toughness of PLA/PEG films. In contrast, a slight decrease in mechanical properties was observed when the content of CNFs reached 0.83 phr. Considère's constructions are used to explain the neck phenomena and cold drawing of nanocomposite films. The crystallization and thermal stability of PLA nanocomposite films were enhanced, with a slight decrease in cold-crystalline temperature (T cc) and an increase in decomposition temperature (T d).

Applicability of enzymatic and phenol–sulfuric acid methods for determination of cellulose nanofibers in ecotoxicity testing

In parallel with the development of novel materials, such as cellulose nanofibers (CNFs), their effects on aquatic organisms should be evaluated. In ecotoxicity testing, concentration measurements are important to obtain accurate exposure concentrations; however, few studies have measured the concentration and dispersion state of CNFs in test solutions. Therefore, we evaluated the applicability of enzymatic and phenol–sulfuric acid methods for CNF quantification in ecotoxicity testing. In the enzymatic method, CNF content was determined by quantifying the d-glucose produced from the CNFs using cellulase with a glucose assay kit. Three types of cellulases were purchased, and impurities such as d-glucose were identified and removed. The differences in CNF degradation efficiency among the cellulases were evaluated, and a cellulase suitable for CNF degradation was selected. In the phenol–sulfuric acid method, a microplate-based method was employed to handle a large number of samples. We demonstrated that both the enzymatic and phenol–sulfuric acid methods could quantify CNFs in media for ecotoxicity testing. The enzymatic method was able to measure lower CNF concentrations (~ 1 mg/L) than the phenol–sulfuric acid method (~ 10 mg/L) and had less interference with CNF quantification by algae and non-cellulosic polysaccharides.

Anti-freezing hydrogel regulated by ice-structuring proteins/cellulose nanofibers system as flexible sensor for winter sports

Conductive hydrogels are widely used as sensors in wearable devices. However, hydrogels cannot endure harsh low-temperature environments. Herein, a new regulatory system based on natural ice-structuring proteins (ISPs) and cellulose nanofibers (CNFs) is introduced into hydrogel network consisting of chemically crosslinked network of copolymerized acrylamide and 2-acrylamide-2-methylpropanesulfonic acid, and physically crosslinked polyvinyl alcohol chains, affording an anti-freezing hydrogel with high conductivity (2.63 S/m). These hydrogels show excellent adhesion behavior to various matrices (including aluminum, glass, pigskin, and plastic). Their mechanical properties are significantly improved with the increase in CNF content (tensile strength of 106.4 kPa, elastic modulus of 133.8 kPa). In addition, ISPs inhibit the growth of ice. This endows the hydrogels with anti-freezing property and allows them to maintain satisfactory mechanical properties, conductivity and sensing properties below zero degrees. Moreover, this hydrogel shows high sensitivity to tensile and compressive deformation (GF = 5.07 at 600–800 % strain). Therefore, it can be utilized to develop strain-type pressure sensors that can be attached directly to human skin for detecting various body motions accurately, reliably, and stably. This study proposes a simple strategy to improve the anti-freezing property of hydrogels, which provides new insights for developing flexible hydrogel electronic devices for application in winter sports.

Cross-linking lignin and cellulose with polymers using siloxane compounds

Siloxanes are a group of substances characterized by Si-O-Si functional group. Siloxanes can react with alcohols to form Si-O-C bond. Siloxanes have been widely used as crossing linking agents and graft copolymers as well as additives for plastics. Lignin contains both phenolic and aliphatic hydroxy groups which have the potential to instigate bonding with siloxane compounds. However, there has not been any attempt to apply siloxanes as crosslinking agents for biobased composite formation. This manuscript presents the first study of applying siloxanes compounds to lignin and Cellulose nanofibers (CNF) with respective PLA, PETG, and HDPE to prepare biocomposites. Both Tetramethyl Tetraphenyl Trisiloxane (TTT) and Tetraethoxysilane (TEOS) were used as cross-linking agents. We have successfully incorporated 20 wt% lignin and 10 wt% CNF into the biocomposite filaments. The tensile properties of ensuing biocomposite were investigated. The objective of this work is to demonstrate the potential of lignin and CNF as a sustainable co-polymer to improve the properties of PLA/PETG/HDPE-based materials for 3D printing. This paper will also discuss the challenges and opportunities associated with the use of lignin in 3D printing, including the effect of lignin and CNF content on the mechanical and thermal properties, the compatibility of lignin and CNF with PLA/PETG/HDPE, and the potential for further optimization of the cross-linking chemistry using TTT and TEOS.

High‐velocity impact behavior and quasi‐static indentation of new elastomeric nanocomposites reinforced with cellulose nanofibers and lignin powder

AbstractThe present study investigates the indentation resistance of elastomeric nanocomposites based on natural rubber with different amounts of cellulose nanofibers (CNFs) under quasi‐static indentation (QSI) and high‐velocity impact (HVI) tests. At first, the baking characteristics and hardness of the samples were checked. The results showed that with the increase in CNFs content, the hardness of the samples increases, and the optimal baking time decreases. A high‐quality final product is produced through good dispersion and acceptable physical bonding between the CNF filler and the rubber chain. Further, the results of quasi‐static indentation showed that the amount of energy absorption for optimal loading of 6 phr increased by 43% compared to a control sample (0 phr). Similarly, from the high‐speed impact results for optimal loading (6 phr), the ballistic limit and energy absorption values increased by 23.6 and 52.7%, respectively, compared to the control sample (0 phr). It was also observed for higher values (9,12 phr) that the glass transition temperature, Tg, effect significantly affected the fracture behavior of the samples due to the high‐speed impact. Finally, CNFs provide better bonding with polymer chains to improve properties through good interaction with natural rubber, making them suitable for energy absorption applications.Highlights New elastomeric nanocomposites reinforced with cellulose nanofibers were made. Increasing the amount of CNFs decreases the optimum curing temperature. The hardness of elastomeric nanocomposites is increased by cellulose nanofibers. The indentation properties of nanocomposites have increased significantly. The optimum value of 6‐phr increased the impact resistance of nanocomposites.

Cellulose nanofiber-introduced continuous-ramie yarn-reinforced polylactic acid filament for 3D printing: Novel fabrication process and mechanical properties

This study focused on reinforcing the interface of continuous-ramie yarn-reinforced polylactic acid (PLA) filaments with cellulose nanofibers (CNFs) for 3D printing applications. To realize the reinforcement effect of CNFs, the distribution of dispersed CNFs at the surface of ramie fiber is necessary. Thus, we developed a new false-untwisting process to enable the continuous dip-coating of CNF slurry while the ramie yarn is untwisted yarn. This study was designed to reveal the influence of the false-untwisting process and CNF content on the surface morphology of the processed yarn and on the mechanical properties of the yarn–PLA composite filaments. We found that the false-untwisting process achieved the formation of fuzzy CNFs. Furthermore, the tensile strength and Young’s modulus of the filaments were improved by up to 20.0% and 26.6%, respectively, compared to those of ramie yarn-reinforced PLA filaments without CNFs.

Optimized PCL/CNF bio-nanocomposites for medical bio-plotted applications: Rheological, structural, and thermomechanical aspects

The use of bioabsorbable and biodegradable composites in the medical field has experienced significant growth. Cellulose nanofibers (CNF) have been employed to reinforce medical-grade poly[ε-caprolactone], enhancing both its load-bearing capacity and stiffness compared to pure polycaprolactone PCL. The manufacturing process involved a series of steps applied to five different grades of PCL/CNF filaments. Initially, melt extrusion and pelletization were performed on the filament, followed by 3D bioplotting to create the specimens. The influence of CNF reinforcement on poly[ε-caprolactone] was evaluated through a range of tests, including rheological, thermomechanical, and in situ micromechanical assessments. To further characterize the samples, Micro-Computed Tomography and Scanning Electron Microscopy fractography were employed for the microstructural and morphological analyses, respectively. The mechanical properties of poly[ε-caprolactone]/CNF composites with 6 wt % CNF content exhibited a 23.8% increase in tensile strength and a 19.1% increase in flexural strength compared to the pure matrix, while also displaying minimal porosity.

Water vapor permeability of smooth cellulose nanofiber film prepared via spraying

Eco-friendly and greener barrier materials are required to replace the synthetic packaging materials as they produce a threat to environment. These can be fabricated by natural polymers such as cellulose nanofiber (CNF). The sustainability of CNF was so amazing due to its potential for circular economy and provides alternative platform for synthetic plastics. The challenging task to fabricate CNF films still existed and also current methods have various limitations. CNF films have good oxygen permeability and the value was lower than synthetic plastics. However, CNF films have poor water vapour permeability and higher than that of synthetic plastics. The fabrication method is one of strong parameters to impact on the water permeability of CNF films. The deposition of CNF suspension on the stainless-steel plate via spraying, is a potential process for fabrication for CNF films acting as barrier material against water vapour. In spraying process, the time required to form CNF films in diameter of 15.9 cm was less than 1 min and it is independent of CNF content in the suspension. The uniqueness of CNF films via the spraying process was their surfaces, such as rough surface exposed to air and smooth surface exposed to stainless steel. Their surfaces were investigated by SEM, AFM and optical profilometry micrographs, confirming that the smooth surface was evaluated notable lower surface roughness. The spray coated surface was smooth and glossy and its impact on the water vapor permeability remains obscure. The spraying process is a flexible process to tailor the basis weight and thickness of CNF films can be adjusted by the spraying of CNF suspension with varying fibre content. The water vapour permeability of CNF films can be tailored via varying density of CNF films. The plot between water vapour transfer rate (WVTR)/water vapour and density of CNF films has been investigated. The WVP of spray coated CNF films varied from 6.99 ± 1.17 × 10−11 to 4.19 ± 1.45 × 10−11 g/m.s.Pa. with the density from 664 Kg/m3 to 1,412.08 Kg/m3. The WVP of CNF films achieved with 2 wt% CNF films (1,120 Kg/m3) was 3.91 × 10−11 g/m.s.Pa. These values were comparable with the WVP of synthetic plastics. Given this correspondence, CNF films via spraying have a good barrier against water vapour. This process is a potential for scale up and commercialization of CNF films as barrier materials.

Synergistic Toughening of Epoxy Composite with Cellulose Nanofiber and Continuous Pineapple Leaf Fiber as Sustainable Reinforcements.

In this work, the effect of cellulose nanofiber (CNF) on the mechanical properties of long pineapple leaf fiber (PALF)-reinforced epoxy composites was investigated. The content of PALF was fixed at 20 wt.% and the CNF content was varied at 1, 3, and 5 wt.% of the epoxy matrix. The composites were prepared by hand lay-up method. Comparison was conducted between CNF-, PALF- and CNF-PALF-reinforced composites. It was found that the introduction of these small amounts of CNF into epoxy resin caused very small effects on flexural modulus and strength of neat epoxy. However, impact strength of epoxy with 1 wt.% CNF increased to about 115% that of neat epoxy, and, as the content of CNF increased to 3 and 5 wt.%, the impact strength decreased to that of neat epoxy. Observation of the fractured surface under electron microscope revealed the change in failure mechanism from a smooth surface to a much rougher surface. For epoxy containing 20 wt.% PALF, both flexural modulus and strength increased significantly to about 300% and 240% that of neat epoxy. The composite impact strength increased to about 700% that of the neat epoxy. For hybrid systems containing both CNF and PALF, there were few changes observed in both flexural modulus and strength compared to the PALF epoxy system. However, much improvement in impact strength was obtained. By using epoxy containing 1 wt.% CNF as the matrix, the impact strength increased to about 220% that of 20 wt.% PALF epoxy or 1520% that of neat epoxy. It thus could be deduced that the spectacular improvement in impact strength was due to the synergistic effect of CNF and PALF. The failure mechanism leading to the improvement in impact strength will be discussed.

Mechanical strength predictability of full factorial, Taguchi, and Box Behnken designs: Optimization of thermal settings and Cellulose Nanofibers content in PA12 for MEX AM

Optimization of reinforced nanocomposites for MEX 3D-printing remain strong industrial claims. Herein, the efficacy of three modeling methods, i.e., full factorial (FFD), Taguchi (TD), and Box-Behnken (BBD), on the performance of MEX 3D printed nanocomposites was investigated, aiming to reduce the experimental effort. Filaments of medical-grade Polyamide 12 (PA12) reinforced with Cellulose NanoFibers (CNF) were evolved. Besides the CNF loading, 3D printing settings such as Nozzle (NT) and Bed (BΤ) Temperatures were optimization goals aiming to maximize the mechanical response. Three parameters and three levels of FFD were compliant with the ASTM-D638 standard (27 runs, five repetitions). An L9 orthogonal TD and a 15 runs BBD were compiled. In FFD, wt.3%CNF, 270 °C NT, and 80 °C BΤ led to 24% higher tensile strength compared to pure PA12. TGA, RAMAN, and SEM analyses interpreted the reinforcement mechanisms. TD and BBD exhibited fair approximations, requiring 7.4% and 11.8% of the FFD experimental effort.

Versatile Assembly of Metal-Phenolic Network Foams Enabled by Tannin-Cellulose Nanofibers.

Metal-phenolic network (MPN) foams are prepared using colloidal suspensions of tannin-containing cellulose nanofibers (CNFs) that are ice-templated and thawed in ethanolic media in the presence of metal nitrates. The MPN facilitates the formation of solid foams by air drying, given the strength and self-supporting nature of the obtained tannin-cellulose nanohybrid structures. The porous characteristics and (dry and wet) compression strength of the foams are rationalized by the development of secondary, cohesivemetal-phenolic layers combined with a hydrogen bonding network involving the CNF. The shrinkage of the MPN foams is as low as 6% for samples prepared with 2.5-10% tannic acid (or condensed tannin at 2.5%) with respect to CNF content. The strength of the MPN foams reaches a maximum at 10% tannic acid (using Fe(III) ions), equivalent to a compressive strength 70% higher than that produced with tannin-free CNF foams. Overall, a straightforward framework is introduced to synthesize MPN foams whose physical and mechanical properties are tailored by the presence of tannins as well as the metal ion species that enable the metal-phenolic networking. Depending on the metal ion, the foams are amenable to modification according to the desired application.

Significant enhancement in hydrogen evolution rate of 2D bismuth oxychloride lamellar membrane photocatalyst with cellulose nanofibers

Photocatalytic hydrogen evolution (PHE) is a sustainable alternative for generating green and clean energy. However, it requires the use of nanoscale photocatalysts, whose applicability is limited by their poor reusability and proton release from water molecules. Herein, a porous two-dimensional lamellar membrane (2DLM) photocatalyst was fabricated from bismuth oxychloride (BiOCl) nanosheets (BNs) and cellulose nanofibers (CNFs) via layer-by-layer self-assembly. The hybridization of the CNFs with the BNs improved the PHE rate of the resulting BiOCl/CNFs membrane (BCM). The optimal PHE rate was observed for a CNF content of 3.2 wt% and was 4.7-times that of raw BNs dispersed in an aqueous solution alone and 1.85-times that of the BiOCl membrane (BM). Moreover, the PHE rate remained unchanged even after 10 discontinuous cycles for a total time of 60 h. Comprehensive experimental characterization and molecular dynamics simulations confirmed that the introduction of the CNFs effectively regulated the hydrogen bond network of the confined water molecules, thus improving the efficiency of the conversion of H2O into H2. Meanwhile, the optimization of the nanochannel sizes of the BNs by the hybridized CNFs accelerated water transport within the nanochannels. The 2DLM also showed excellent mechanical strength, flexibility, and translucence. This strategy of fabricating 2DLMs using a nanosheet photocatalyst and CNFs not only results in improved PHE performance but also should also aid the development of stable and reusable photocatalysts for other industrial applications.

Synthesis of cellulose nanofiber/polysiloxane-polyurea composite materials with self-healing and reprocessing properties

Inspired by the self-recoverability ability of organisms, various self-healing materials have been developed. However, most reinforced fillers are faced with the problem that mechanical strength and self-healing efficiency of materials cannot be improved simultaneously. Here we first prepared new polysiloxane-polyurea (PDMS-PU) and used it as matrix resin to prepare cellulose nanofiber (CNF)/PDMS-PU composite materials with high mechanical properties. CNFs increased the tensile strength of PDMS-PU by 38.87 % and CNF/PDMS-PU composite materials maintained the great bending resistance, transparency and reprocessing properties of PDMS-PU. Moreover, the introduction of CNFs did not reduce the self-healing efficiency of PDMS-PU, and PDMS-PU containing disulfide bonds with CNF content of 1 % (CNF/PDMS-IPDI-S-1 %) with healing efficiency of 95.58 %, and the tensile strength after three recycling processing was still as high as 92.55 % of the original. CNFs reinforced PDMS-PU composite materials are expected to replace PDMS materials in advanced engineering fields that require high strength durability and good formability.

Influence of Cellulose Nanofibers on the Behavior of Pickering Emulsions. Part 1. Microscopy and Startup Flow Test

The dispersibility of flexible polymer chains present at the emulsion's interface between the dispersed and continuous phase has obvious effects on rheology and dielectric properties of the whole emulsion. Cellulose nanofiber (CNF)-based Pickering emulsions are good systems to research these properties with respect to their microscopic phase structure, dielectric, and rheological properties by using CNF as a water-dispersible Pickering emulsifier, liquid paraffin as an oil phase, and didodecyldimethylammonium bromide (DDAB) as a cationic auxiliary surfactant. The CNF and DDAB contents were systematically varied while the water-to-paraffin oil ratio was kept constant to discern the influence of the Pickering emulsifiers. Polarized optical microscopic images reveal that the droplets tend to shrink at higher CNF content but grow bigger when increasing the DDAB content, which is proved by fluorescence analysis of the CNF dispersibility with varying DDAB content. The dielectric damping exhibits a minimum, whose value decreases with increasing DDAB and CNF content. Increasing the DDAB content promotes the solubilization of CNF in the aqueous phase, which will increase the overall viscosity and yield points. Similarly, a higher CNF content leads to a higher viscosity and yield point, but at high DDAB contents, the viscosity function exhibits an S-shape at intermediate CNF contents. To evaluate the results further, they were compared with CNF dispersions (without oil phase), which showed a surfactant effect slightly on maximum stress but strongly on yield stress τy, indicating that DDAB can promote the formation of a CNF network rather than the viscosity of the whole system. This paper provides information on how a systematical variation of the composition influences morphology and physico-chemical interactions as detected by broadband dielectric spectroscopy and rheological behavior.

SYNTHESIS OF CELLULOSE-BASED SUPERABSORBENT HYDROGEL FILLED WITH CELLULOSE NANOFIBER FROM OIL PALM EMPTY FRUIT BUNCHES

Oil palm empty fruit bunches (OPEFB) are waste products from the oil palm plantations, which is still an issue in Indonesian plantations. The high cellulose content in OPEFB enables them to be processed into cellulose nanofibers (CNF) that can be applied as fillers in the hydrogel. This research aimed to synthesize cellulose-based superabsorbent hydrogel and observe the optimal condition to produce hydrogel with high absorption and good thermal properties. CNF-based hydrogel is an excellent option to improve the physicochemical characteristics of the hydrogel. In this work, carboxy methyl cellulose hydrogel was firstly prepared by using citric acid. Then, CNF were added as fillers at different ratio variations, such as 0, 1, 3, 5, and 7 wt%. The surface morphology of the hydrogel showed rough surfaces, except for the 7 wt% CNF variation that produced hydrogel with a homogeneous surface. The cross-linking between the hydrogel and the fillers was evaluated by Fourier-Transform Infrared Spectroscopy (FTIR). A peak associated with the carboxylic acid functional group indicated hydrogel formation. The incorporation of CNF did not change the FTIR spectra since both materials had similar structures. Water absorption analysis showed that the developed product could be classified as a superabsorbent since all samples showed a degree of swelling above 200 g.g−1. CNF content at a 1 %wt ratio had the highest water retention and best thermal stability. The hydrogel showed exceptional characteristics, being suitable for various applications, mainly in agricultural sectors that required water delivery to the soil.

Atmosphere‐free activation methodology for holey graphene/cellulose nanofiber‐based film electrode with highly efficient capacitance performance

AbstractAn efficient chamber‐induced activation method was applied for the preparation of holey graphene/cellulose nanofiber‐based film with high specific surface area (SSA) and multiple channels through the graphene nanosheets. With the cellulose nanofiber (CNF) simultaneously serving as “dispersing agent,” “spacer,” and “activating agent,” the graphene oxide (GO) nanosheets are perforated by the pyrolysis gas from CNF in the confined space inside the hybrid films, uniformly dispersed, and sandwiched between CNF networks with less agglomeration and restacking. Additionally, we have proved that H2O and H2 are primarily responsible for the activation and etching of GO/CNF film. As the CNF content increases, the mesoporosity of the activated reduced GO/CNF (A‐RGO/CNF) film increases, and the graphene nanosheets show more nanopore perforations. Benefitting from the high SSA, high density, moderate mesoporosity, and abundant channels for ion diffusion through the graphene nanosheets, the A‐RGO/CNF film exhibits the highest specific capacitance of 323 (236) F g−1 (F cm−3) at 1 A g−1. For the A‐RGO5/CNF5 film containing half CNF and half GO, an excellent comprehensive electrochemical performance including superior rate performance (208 (160) F g−1 (F cm−3) at 60 A g−1) is exhibited. Moreover, the A‐RGO5/CNF5 electrode in an all‐solid‐state flexible symmetric supercapacitor delivers a high specific capacitance of 250 (193) F g−1 (F cm−3) at 1 A g−1. This study provides a novel idea for the preparation of holey graphene‐based film for supercapacitor electrodes. The strategy of simultaneously employing CNF as “dispersing agent,” “spacer,” and “activating agent” also offers a new vision for the assembly of homogeneous nanohybrid material and the utilization of pyrolysis gas.